Electric heater



June 4, 1929.

G. v. SCHMIDT ELECTRI C HEATER Filed NOV. 1925 INVENTOR. BY 650/665 1 Jew/W07" Miriam/Ev Patented June 4, 1929.

PATENT "OFFICE.

GEORGE V. SCHMIDT, OF OAKLAND, CALIFORNIA.

ELECTRIC HEATER.

Application filed November 2, 1925. Serial No. 66,159.

My invention relates to electric heaters,

. and particularly to a heater arranged for the distribution of vection.

An object of the invention is to provide a heater of the class described which provides a comparatively large heating surface for a given power consumption. L

Another object of the invention is to provide a device of the character described which creates and utilizes convection cur-' rents in the air to effect the distribution of the greater part of the heat emanating there .from. g

A further object of the invention is to provide a device of the character described which is especially adapted for use in portable units.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the follow ing descriptionof the preferred form of my invention which 'is illustrated in the drawings accompanying and forming part of the specification. Itis to be understood that I do not limit myself to the showing made by the said drawings and description, as I may adopt variations of the preferred form within the scope of my invention as set forth in the claims; Referring to said drawings:

Figure 1 is a perspective view'of a heater of my invention. 7

Figure 2 is a vertical transverse sectional view of the device.

Figure 3 is a rear view of the heater, part of the view being shown in vertical section through the heating units thereof.

As is well known, the dissemination of heat from electric heaters of the types at present used is mainly by direct or reflected radiation, so that the heat therefrom tends to remain localized rather than distributed through a room,with the result that suchheating has not proved entirely satisfactory even i for small rooms. Furthermore, the heating elements of such heaters have tended to become unduly hot owing to their comparatively small size, which results in preventing sufficiently rapid circulation of air thereabout by convection and the generation of temperatures at exposed parts which are frequently high enough to scorch adjacent objects, Then, too, a further disadvantage heat therefrom by con- I not practicable on account ofthe space reof such heaters has been disclosed in the fact that units arranged for large heat output have been unduly large and hence usually q'uired for them.

In accordance with my invention, however, a heater is provided which entirely lacks the foregoing disadvantages of present heaters, and offers certain special advantages which make it doubly valuable. Briefly expressed, the heater of my invention preferably comprises a plurality of horizontally disposed parallel heating units arranged in a common vertical plane and-provided with obliquely extending radial fins thermally connected thereto and defining a series of oblique parallel air spaces. The heating units are preferably of the enclosed type and the fins are preferably of metal and are arranged to extend directly therefrom, so that heat is distributed outwardly therealong.

Air in contact, with the upper surface of a fin will, of course, become heated and in rising will strike the lower surface of the. fin above to thereby become still further heated as it moves obliquely upwardlyalong the fin surface to finally escape at the front of the stove. The various heated air columns thus united at the front of the stoveproduce a definite upward movement of a column of air of such magnitude that the convection circulation thus created will thus insure an even distribution of the heat in a minimum time.

As illustrated, the heater 5 of my inven tion comprises end portions 6 between which extend a pluralityof horizontally disposed heating units 7. The latter, it will benoted, may be ofany desired structure, but are preferably of the type in which a helii: of sheet resistance wire is embedded in a core of refractory insulating material. The heat generated is arranged to be conducted from the heating units by means of a metallic cylindrical shell 8 surrounding each heating unit and having a pair of oppositely disposed metallic fins 9 extending therefrom.

As hereshown, a fin 9 and half of a shell 8' of the heatingunit. The outer edges 12 of the plates 11 are preferably rolled to tubular form, such rolled edges being here shown extending to the same side of the plate as do the half-shell portions. In this manner, it will now be noted, the rolled edges of a pair of cooperating plates will be disposed on opposite sides of the plane of the plates. It will now be noted that the plates 11 of successive units are arranged to lie in parallel planes which are obliquely disposed to the horizontal. In this manner, when heat is emanating from the heating units, parallel layers of air defined between the various sets of plates 11 will become heated, and move obliquely upwardly toward a side 16 of the heater, such side being hereafter referred to as the front side.

, In order that the air above the upper most heating unit may also be directed to the common stream of warm air created at the front of the heater, a plate 17 is preferably provided, said plate lying above said unit and being provided with a rolled edge portion 18 at the front edge thereof and extending parallel to the other plates to a point rearwardly of'the plane of the rear edges of said latter plates, whence it extends downwardly to a point below the lower portion of the lowest of said plates. In this manner, it will be noted, not only isheated air from above the uppermost heating unit directed outwardly ofthe stove at its front, but the air to be circulated between the various sets of plates is taken from a point adjacent toe floor to thus further increase the circulation effect resulting from the par ticular arrangement of parts hereinbefore described.

Means are also provided for confiningand directing the movement of the air passing beneath the lowermost heating unit and its associated plates. As here shown, such means comprises a plate 21 forming the upper wall of a. chamber 22 of a triangular section, the plate 21 being'parallel to the set of plates above it. The chamber 22, it will be noted, is defined between the plate 21, a horizontal bottom plate 28, and a vertical plate 2. the latter preferably having a rolled edge 26 at its top and being positioned in the plane of the front edges of the heating unit planes. The chamber 22 provides a convenient conduit for the various'connecting wires and, as here shown, a provides an enclosure for the body of a flush switch 27 mounted in the front plate 24:.

The end portions 6 of the heater, it will now be noted, are preferably formed with spaced inner and outer walls 28 and 29 respectively, the former being perforated to to receive the heatin units and, preferably, the ends of the shells 8 and the various rolled edges of the plates, it being noted that the end edges of the fin portions of the various plates are arranged to abut the walls. In this manner, tension rods 30, here shown concealed beneath the plate 17 and in the chamber 22, may be used to hold the inner end walls against the fin ends and thus maintain the various parts of the structure in assembled relation in a simple manner. The space 31 defined between the walls 28 and 29, it will be noted, provides a compartment in which the various connecting wires 32 may be placed, while front, top, and rear edge plates 33, 34: and 35 respectively are arranged to connect the walls 28 and 29 to complete the closure of the space 31, so that such wires may be concealed.

It will now be noted that the air circulating upwardly through the spaces between the various plates is exposed to a maximum of heating surface, with the result that no heating unit plate becomes unduly warm and the temperature of the rolled edges at the front of the stove becomes but little greater than the temperature of the air circulating thereto. The lower and vertical portion of the plate 17 will be maintained at the temperature of the air entering from beneath the heater, while the upper and oblique portion thereof will acquire only the temperature of the heated air. lVith the end spaces 31 serving to provide heat insulation atthe ends of the stove, it will now be clear that no exposed portion of the stove can acquire an unduly high temperature.

It will now be particularly noted that the rolled edges of the various plates, by reason of their size tend to constrict the inlets to and exits from the various passages defined bet-ween them so that the flow of air through the passages is hindered to permit more complete heating thereof. By positioning the plates as hereinbefore described, practically all of the heat radiating from the heating units will be intercepted by the various plate portions, so that all of such heat is rendered available for heating the air column, with the result that substantially all of the heat produced by the heating units is utilized in the process'of heating the air of a room by convection, and the quickest possible distribution of the heat is thus afforded.

It will now be noted that while a portable unit embodying the heater of my invention is here shown, such units may be permanently installed in appropriate wall niches with out changing the structure of the device. And it will be further noted that the number of heating coils used in a unit will be determined solely by the desired thermal'output of the unit in terms of the power. consumption of the coils.

I claim:

1. In a heater, a heat conducting plate carrying a heating. unit extending longitudinally therealong, and closed hollow end members having the opposed faces thereof perforated to receive the ends of said plate and unit in fitted and supported relation.

2. In a heater, a heat conducting plate carrying an electric heating unit thermally associated therewith, and end members arranged to have opposite ends of said plate supportedly secured thereto and providing the sole support for said plate, said members providing closed conduits for the connecting Wires of said unit. 1

3. In a heater, a horizontally disposed electric heating unit, and end members arranged to have the extremities of said unit extend thereinto through a'wall thereof and providing closed conduits for connecting Wires at said extremities of said unit, said Walls providing the sole support for said unit. 1

In testimony whereof, I have hereunto set my hand at Oakland, California, this 27th day of October, 1925. V

GEORGE V. SCHMIDT. 

